body {
    background-color: rgb(18, 28, 43);
    margin: 0;
}
#title {
    width: 800px;
    height: 70px;
    /* div居中 */
    margin: 0 auto ; 
    /* 文本居中 */
    text-align: center; 
    /* 字体颜色 */
    color: white;
    /* 背景图设置 */
    background-image: url(../img/head.gif);
    background-repeat: no-repeat;
    background-position: center center;
    background-size: 500px;
}
/* 画图区整体设置 */
#center {
    display: flex;
    flex-direction: row;
    justify-content: center;
    /* 画框调试 */
    /* border-style: solid;
    border-width: 2px; */
}
/* 左中右三列设置 */
.cbox {
    /* 调试用边框，调试完了就去掉 */
    /* border-width: 2px;
    border-style: solid; */
}
#center-l , #center-r {
    width: 28%;
    height: 850px;
}
#center-m {
    width: 44%;
    height: 850px;
}
.box {
    border-color:rgb(11, 196, 233);
    border-width: 2px;
    border-style: solid;
    border-radius: 3%;
    margin: 10px 10px;
}
/* 上面这一列一分为二，1：1 */
.mbox {
    height: 30%;
    width: 95%;
    border-style: solid;
    border-color: rgb(11, 196, 233);
    border-width: 2px;
    border-radius: 2%;
    margin: 5px auto;
}
#t4 {
    height: 61%;
}